TUESDAY, July 11, 2006 (HealthDay News) -- Any kind of exercise will help extend your life, say researchers who used a sophisticated test to arrive at that conclusion.
"There are plenty of reports out there saying that self-reported exercise like running or jogging is beneficial," said lead researcher Todd M. Manini, an exercise physiologist at the U.S. National Institute on Aging. "We wanted to see if just usual daily activity had a protective value."
His team's six-year study of 302 people between 70 and 82 years of age found that any sort of energy expenditure through physical activity was associated with a lower risk of death.
That finding, published in the July 12 issue of the Journal of the American Medical Association, is not entirely surprising. Organizations such as the American Heart Association have long said that some physical activity is better than none. What was unusual about this study was the exquisitely detailed measurements used to determine levels of physical activity, Manini said.
In the study, the researchers had volunteers drink water containing two harmless isotopes, oxygen-18 and hydrogen-2. Oxygen-18 is eliminated from the body in water, while hydrogen-2 is eliminated not only in water but also in carbon dioxide, which is produced during energy expenditure. So, by measuring levels of water and carbon dioxide leaving the body, the researchers were able to get accurate readings of daily energy expenditure.
"The technique has been around for use in humans for 20 years," Manini said. "It is kind of expensive for a large-scale study, and also requires special expertise."
Following the participants for six years, the researchers found that death rates went down as daily energy expenditure went up. In fact, seniors in the highest third of daily energy expenditure had a 69 percent lower risk of dying than those in the lowest third.
"The study doesn't tell you what the people did -- just the quantity of energy expended," Manini said. But it didn't seem to matter if energy was expended in daily chores or a workout at the gym. "Like other studies, we asked people what they did," Manini said. "There was no difference with or without structured exercise."
People in the highest third of expended energy were more likely to work for pay and walk two flights of stairs a day, he said. They burned an average of 600 calories more a day than those in the lowest third, he said.
That 600 calories represents "about two hours of activity," Manini said. "It doesn't have to be a certain activity. It can include washing dishes, vacuuming and sweeping, as well as structured exercise."
"We were quite surprised to find this effect with a relatively small number of participants," said co-researcher Dr. James Everhart, chief of the epidemiology and clinical trials branch of the U.S. National Institute of Diabetes and Digestive and Kidney Diseases. "When we started talking about it, maybe 10 years ago, we thought we would need twice as many participants to show an effect."
The study "has objectively shown that energy use is associated with a lower risk of dying," Everhart said.
It's the finding on the type of energy use deemed necessary that will interest many people who want to prolong their lives, but not undertake an intensive exercise program. The American Heart Association -- which officially recommends at least 30 minutes of brisk activity every day -- suggests a number of ways to achieve that goal without actually exercising. These include simple things such as pushing a lawnmower rather than riding one, walking the dog, parking on the far side of the shopping center and walking to the store, and even standing rather than sitting while talking on the telephone.
For more tips on healthy, everyday activities, head to the American Heart Association.